Eimeria kinsellai is an apicomplexan parasite of the genus Eimeria that infects the marsh rice rat. It was discovered in 1970 at Paynes Prairie, Alachua County, Florida. A different Eimeria, Eimeria palustris, has been found in Alabama marsh rice rats. E. kinsellai differs from other Eimeria found in rice rats, such as Eimeria couesii, Eimeria oryzomysi, Eimeria ojastii, and E. palustris, in anatomical details. It was named after parasitologist John M. Kinsella.
Notocotylus fosteri is a parasitic fluke that infects the marsh rice rat in Florida.
Maritrema heardi is a parasitic fluke that infects the marsh rice rat in a salt marsh at Cedar Key, Florida. It was first listed as Maritrema sp. II in 1988, then described as the only species of a new genus, Floridatrema heardi, in 1994, and eventually reassigned in 2003 to Maritrema as Maritrema heardi. Its intermediate host is the fiddler crab Uca pugilator and it lives in the intestine of the marsh rice rat, its definitive host. Together with two other species of Maritrema, it is very common in affected marsh rice rats; it infects 19% of studied rats at Cedar Key. According to Tkach and colleagues, M. heardi is probably primarily a parasite of birds that has secondarily infected the marsh rice rat. Floridatrema was distinguished from Maritrema on the basis of its possession of loops of the uterus that extend forward to the place where the intestine is forked or even to the pharynx. Genetically, M. heardi may be closest to the morphologically similar M. neomi, which infects Neomys water shrews in the Carpathians.
Ascocotyle angrense is a fluke in the genus Ascocotyle that mainly infects birds. It has previously been confused with A. diminuta, which infects fish-eating birds and raccoons. It has also been recorded from the marsh rice rat in a saltwater marsh at Cedar Key, Florida, where it occurred in 25% of animals.
Ascocotyle pindoramensis is a fluke in the genus Ascocotyle that occurs along the eastern coast of the Americas from Brazil to Nicaragua, Mexico, Louisiana, and Florida and doubtfully in Egypt. It occurs in the intestine of its definitive hosts. Hosts recorded in the wild include the least bittern, roseate spoonbill, great blue heron, striated heron, stripe-backed bittern, yellow-crowned night heron, black-crowned night heron, osprey, Neotropic cormorant, and marsh rice rat. In the marsh rice rat, it infected 9% of rats examined in a 1970–1972 study in the salt marsh at Cedar Key, Florida, but none in a freshwater marsh. A. pindoramensis has been experimentally introduced into the domestic duck, chicken, dog, house mouse, and golden hamster. It occurs in various body parts of its intermediate hosts—the poeciliid fish Phalloptychus januarius, Poecilia catemaconis, Poecilia mexicana, Poecilia mollienisicola, Poecilia vivipara, and a species of Xiphophorus and the cichlid Tilapia. It was first described as Pygidiopsis pindoramensis in 1928 and subsequently as Pseudoascocotyle mollienisicola in 1960. The latter species was moved to Ascocotyle in 1963, but only in 2006 it was recognized that the two represent the same species, which is now known as Ascocotyle pindoramensis. Other flukes from Argentina and Mexico that were identified as Pygidiopsis pindoramensis instead represent a different species of Pygidiopsis.
Catatropis johnstoni is a fluke from the United States. It was first described in 1956 by Martin, who had found cercariae released by the snail Cerithidea californica in southwestern California. When the cercaria were fed into chickens, they developed into mature worms; Martin speculated that the natural host was a waterbird. In 1970, a study of helminths of the marsh rice rat in a saltmarsh at Cedar Key, Florida, found flukes similar to C. johnstoni. The fluke was present in 30% of 110 examined rice rats, with the number of worms per rat varying from 1 to 500. Some Cerithidea scalariformis snails from this marsh also released cercariae similar to C. johnstoni from California. When introduced into chickens, marsh rice rats, Mongolian gerbils, golden hamsters, and house mice, these cercariae developed into infectious flukes. Bush and Kinsella, who reported on the result in 1972, regarded the Florida and California flukes as the same species, as there were only minor size differences between them. Because no marsh-inhabiting rodent occurs in both California and Florida, they agreed with Martin that the normal host of C. johnstoni was most likely a bird, perhaps a rail or shorebird. Nevertheless, the rate of infection in the rice rat is too high for it to be just an accidental host; perhaps C. johnstoni is restricted to saltmarshes but not host-specific.
Echinochasmus schwartzi is a fluke that infects dogs, muskrats, and marsh rice rats. It uses Fundulus fish as its intermediate host. Adults are similar to Echinochasmus microcaudatus, but differ in features of the oral sucker.
Maritrema prosthometra is a parasitic fluke from North America. It was first described in 1969 from the intestine of the clapper rail in eastern North America. Later, it was also found in the small intestine of 5% of a sample of marsh rice rats collected in a salt marsh at Cedar Key, Florida, where it used the fiddler crab Uca pugilator as an intermediate host.
Microphallus basodactylophallus is a species of digenean parasite in the genus Microphallus. It was first described in 1969, as Carneophallus basodactylophallus, from southern Louisiana, where the raccoon is the definitive host, the first intermediate host is the snail Lyrodes parvula, and the second intermediate host is the crab Callinectes sapidus. It was later moved to the genus Microphallus. In 1988, John Kinsella recorded it from the marsh rice rat in a saltmarsh at Cedar Key, Florida. There, it was one of the most prevalent parasites in the marsh rice rat and used C. sapidus as an intermediate host.
Odhneria odhneri is a digenean parasite in the genus Odhneria of family Microphallidae. It infects several species of shorebirds, including the willet, as well as the marsh rice rat.
Probolocoryphe glandulosa is a digenean parasite in the genus Probolocoryphe of family Microphallidae. Recorded hosts include the clapper rail, ruddy turnstone, raccoon, little blue heron, Wilson's plover, black-bellied plover, and marsh rice rat.
Acanthotrema cursitans is a species of fluke in the genus Acanthotrema. It infects the marsh rice rat Oryzomys palustris, the raccoon Procyon lotor, the Virginia opossum Didelphis virginiana, the snail Cerithidea scalariformis, and killifishes of the genus Fundulus on the Gulf Coast of Florida. It was first described as Cercaria cursitans in 1961, then moved to Stictodora in 1974, and to Acanthotrema in 2003.
Urotrema scabridum is a fluke in the genus Urotrema of family Urotrematidae. Recorded hosts include:
Capillaria gastrica is a parasitic nematode in the genus Capillaria. Among the known host species are the marsh rice rat and deermouse.
Opisthorchiidae is a family of digenean trematodes. Opisthorchiidae have cosmopolitan distribution.
Parastrongylus schmidti is a species of parasitic nematode in the genus Parastrongylus. It was first described as Angiostrongylus schmidti in 1971 from the marsh rice rat in Florida, but later assigned to Parastrongylus.
Opecoelidae is a family of trematodes. It is the largest digenean family with over 90 genera and nearly 900 species, almost solely found in marine and freshwater teleost fishes. It was considered by Bray et al. to belong in the superfamily Opecoeloidea Ozaki, 1925 or the Brachycladioidea Odhner, 1905.
Acanthotrema is a genus of trematodes in the family Heterophyidae.
